My first Safety Raiser cost me $19.95 and treated my Unitrac arm very gently, for 30 years.
Ten years ago it got a bit too energetic, so: found a NOS/NIB replacement and paid $129.00 (gladly). The box still had the $19.95 tag on it.
A little trick that makes adjusting the Raiser a snap:
Stretch the thinnest O-ring you can locate over the inner tube, to hold your height adjustment, while you determine/lock the horizontal position.